ortmann: south American naiades. 609 



The height of lingulaUi is given as 92 mm., hut there surely is a mistake in 

 this statement. According to the figure, it would he 53 pr. ct. of the length. 



Remarks. — The characters of this sjx'cies are its rather regular, subovate, 

 or subclliptical, outline, with a blunt point behind, somewhat elevated above the 

 base-line. The shell is not very long and of considerable thickness. The peculiar 

 green in the color of the epidermis is remarkable, but is not always present. 



Anatomy. — The soft parts of two males are at hand for examination. 



The structure is typical of the genus. The pajMlhe of the branchial ojjening 

 are very small. The inner edge of the anal and branchial is brown. The palpi 

 are of medium size, semicircular, with a short jjosterior truncation, forming the 

 posterior margins, which are not united. The septa of the gills are irregularly 

 stronger and weaker. 



56. Anodontites ha.semani Ortmann, sp. nov. 

 Shells: Plate XLII, figs. 6, 7. 



Type-locality. — Headwaters of the Rio Paraguay', Santa Rita, Matte Grosso, 

 Brazil (J. D. Haseman coll., June 12, 1909). Type-set: Carn. Mus. Cat. No. 

 61.5832. Four specimens, among them two males and a gravid female with soft 

 parts. 



Characters of the Shell. — Shell moderately thick, outline subovate, narrower 

 in front, broader (higher) behind, not pointed. Height 63 to 67 pr. ct. of the length. 

 Valves not gaping. Dorsal margin gently curved, the part behind the beaks almost 

 straight ; anteriorly to the beaks it descends distinctly, and passes into the anterior 

 margin in an indistinct, obtuse angle. At the posterior end the upper margin forms 

 a more distinct, obtuse angle. Posterior margin obliquely descending, gently 

 convex, broadly curving around at the posterior end into the lower margin. The 

 latter is gently curved, and runs forward and upward, being almost straight in 

 the anterior part, finally curving up into the anterior margin. Thus the shell is 

 distinctly narrowed anteriorly, the greatest height being located at about the be- 

 ginning of the posterior third of the shell, and the shell being somewhat obliciue. 



Valves rather convex, diameter 42 to 47 jm-. ct. of the length. Beaks rather 

 inflated, but only moderately elevated above the hinge-line, located at 27 to 33 

 pr. ct. of the length. Convexity of valves rather regular, greatest over the posterior 

 ridge, which is indistinct, very slightly compressed upon the posterior slope, with- 

 out perceptible flattening upon the sides of the disk. Posterior slojie with indistinct 

 and faint traces of one or two radial ribs. 



Epidermis very slightlj' shining, with crowded, irregular, fine, subconcentric 



